BEDMINSTER, N.J., Aug 10 (Reuters) - U.S. President Donald Trump attacked his own party's Senate majority leader, Mitch McConnell, for a second day on Thursday, complaining from the steps of his private New Jersey golf club about Republicans' failure to repeal and replace Obamacare.

"I just want him to get repeal and replace done. I've been hearing repeal and replace now for seven years ... Mitch, get to work and let's get it done," Trump told reporters at a briefing on his vacation.

In the aftermath of last month's collapse in the Senate of a years-long Republican campaign to gut the 2010 Affordable Care Act, commonly called Obamacare, Trump has berated McConnell and other Republican senators, urging them to return to the divisive issue of reforming the U.S. healthcare insurance system.

Many senators, including McConnell, have been making the case that it is time to move on to other policies, such as tax reform and improving infrastructure.

Asked at the briefing in Bedminster, New Jersey, if McConnell should consider stepping down as Senate Republican leader, Trump said: "If he doesn't get repeal and replace done, and he doesn't get taxes done ... and if he doesn't get a very easy one to get done - infrastructure - if he doesn't get them done, then you can ask me that question."

But Trump also said, "Where is repeal and replace? Now I want tax reform and tax cuts... so I say tax cuts, tax reform and I want a very big infrastructure bill."

Trump had assailed McConnell on Twitter both Wednesday and Thursday, responding to a speech in which the Senate leader said Trump had "excessive expectations" of Congress on matters such as healthcare and did not understand how long it can take to pass major legislation.

"Can you believe that Mitch McConnell, who has screamed Repeal &amp; Replace for 7 years, couldn't get it done. Must Repeal &amp; Replace ObamaCare!" Trump tweeted on Thursday.

A spokesman for McConnell had no comment on Trump's tweets.

The Senate's most senior Republican declared his support of McConnell. Senator Orrin Hatch, who is president pro tempore of the Senate, said on Twitter that McConnell "has been the best leader we've had in my time in the Senate, through very tough challenges. I fully support him."

McConnell's efforts to push through a healthcare bill collapsed last month when he failed to reconcile conflicting demands among conservatives and moderates in the party and get all of the Republicans in the Senate behind the legislation. The House passed its version of a healthcare bill in May.

Alienating the Senate majority leader could make it far more difficult for Trump to achieve his legislative goals.

Trump has failed to notch a major legislative win since taking office in January, although Republicans control both the Senate and House of Representatives. The administration has also been mired in investigations into contacts between his presidential campaign and Russia, and distracted by infighting among high-level White House staff.

McConnell, in a speech on Monday in his home state of Kentucky, said the administration had set too many artificial deadlines and was disappointed when lawmakers did not meet them.

"Our new president, of course, has not been in this line of work before. And I think he had excessive expectations about how quickly things happen in the democratic process," McConnell said.

The blame game between the president, a real estate businessman who had never previously held public office, and McConnell coincides with opinion polls showing public approval rating for Congress and Trump dipping to new lows. A RealClearPolitics average of opinion polls shows approval for the job the president is doing at 37.9 percent, while just 15.7 percent approve of the work Congress is doing. (Reporting by James Oliphant, Doina Chiacu and Susan Cornwell; Editing by Frances Kerry and Grant McCool)